The war between the Mercedes stars imploded in Monaco, where Rosberg won, and the German got some more wind in his sails two weeks ago in Canada, where Lewis Hamilton's car failed.

Rosberg, now leading the championship by 22 points after 7 races, said this week it had been crucial to break Briton Hamilton's four-race winning streak.

"If you have those results behind you, like I do now, it gives you that little bit extra, that little bit of an edge, so it does help," he said. "It's important."

Hamilton, however, is determined to fight back.

On social media, adding hashtags like 'never give up' and 'let's go', he has been posting photos of himself training in the gym, one of them topless as he declared he is "fighting hard to win this championship".

"67kg, down from 73 last year," Hamilton revealed.

On his official website, the 2008 world champion's Austria preview quoted him as saying: "There's a long, long way to go.

"I caught up before and I can catch up again. It's going to take another four wins to make the difference so I'm going to do my best to get those results," said Hamilton.